Note: Descriptions are shown in the official language in which they were submitted.
` Case 1416
LIQUID ISOCYANURATE GROUP-CONTAINING
POLYISOCYANATE MIXTURES OF 4,4'- AND
2,4'-DIPHENYLMETHANE DIISOCYANAT~, METHOD
FOR THEIR PREPARATION AND THEIR USE IN
POLYURETHANE OR POLYISOCYANURATE PLASTICS
I
1. Field of the Invention
This invention pertains to the field of modified
isocyanates. More specifically, it relates to isocyanurate-
containing diphenylmethane diisocyanates
2. Description of the Prior Art
It is known that organic isocyanates can be
trimerized into isocyanurates with the aid of catalysts.
In existing literature, for example in High
Polymers, Vol. XVI, "Polyurethane, Chemistry and
Technology," Pt. I, by J. H. Saunders and K. C. Fresh
(Verlag Intrusions Publishers: New York, London 1962),
p. 94 if., numerous catalysts are described for cyclization
and polymerization. Typical examples are: strong bases
like qua ternary ammonium hydroxides, for example, benzyltri-
methyl ammonium hydroxide, alkali metal hydroxides, for
example sodium or potassium hydroxide, alkali metal alkox-
ides, for example sodium methyl ate and potassium is-
propylate, trialkylphosphines, for example triethylphos-
pine, alkylaminoalkylphanols, for example trussed-
methylaminomethyl)phenol, 3- and/or 4-substituted pardons,
for example 3- or 4-methylpyridine, metal-organic salts, for
Lo
example tetrakis(hydroxyethyl)-sodium borate, Friedel-Crafts
catalysts, for example aluminum chloride, iron (III3
chloride, boron fluoride, and zinc chloride, and alkali
metal salts of weak organic acids and nitrophenolates, for
example, potassium octet, potassium 2-ethyl hexoate,
potassium bonniest, sodium pirate, and potassium phthali-
mode.
Of particular commercial interest in this regard
is the polymerization of organic polyisocyanates to form
polymerization products having an isocyanurate structure and
free isocyanate groups. To do this, it is necessary to stop
the formation of the isocyanurates after the desired degree
of in- or polymerization is achieved. One way to accom-
polish this it by decomposing or neutralizing the gala-
lystq. Thus, basic catalysts can be neutralized, for
example, by acids such as hydrochloric acid.
According to U. S. Patent 2,993,870, various
treason derivatives have proven to be very good catalysts
for the polymerization of aromatic polyisocyanates. The
disadvantage with these catalysts is, on the one hand, thaw
they are already so extremely effective at room temperature
that special measure must be taken involving cleavable,
capped groups if one wishes to obtain polymerization
products with an isocyanura~e structure and free isocyanate
groups. On the other hand, these same treason compounds
-- 2 --
~227~3
are nearly ineffective in the polymerization of aliphatic
polyisocyanates.
In order to overcome this disadvantage in DE-A-26
16 415 co-catalyst systems comprising 1,3,5-~ris(dimethyl-
aminopropyl)-s-hexahydrotriazine and an organic moo- and/or
dicarboxylic acid are used.
The trimerization of aliphatic, cycloaliphatic,
and aromatic polyisocyanates in the presence of complexes of
basic alkali metal compounds and cyclic organic compounds
as catalysts is described in DE-A-31 00 263 REP 56 159). In
this process, the diisocyanates are partially trimerized and
then the excess monomeric diisocyanate it separated off by
means of distillation. The resulting products are print
supply used as paint binders.
In DE-A-25 51 634 (U. S. 4,115,373) Mannish bases
are used as catalysts, and the trimerization is performed in
the presence of inert solvents at temperatures less than
60C. In this method, the solvent must also be separated
from the reaction mixture after completion of trimerization.
The complicated preparation of isocyanurate group-
containing polyisocyanates in the above processes was done
in the desire to obtain relatively high molecular weight
polyisocyanates with a low vapor pressure from extremely
toxic aliphatic or low-boiling point aromatic dozes-
notes. This trimerization unavoidably led to pulses-
7~g~3
notes with r01atively high functionalities, for example,
functionalities of three or more.
However, polyaddition reactions of polyfunctional
compounds with reactive hydrogen atoms and in- and/or
higher functionality polyisocyanates are very difficult to
control and they frequently lead to brittle polyurethane or
pullers which also have low abrasion strength.
Summary of the Invention
The objective of the invention at hand way to
develop polyisocyanates with low vapor pressure which are
liquid at room temperature, storage stable, and easily
processed, and which can be processed into cellular or
noncellular polyurethane, polyisocyanurate, and/or puller
group-containing plastics which exhibit high wear strength,
low flammability, and, in particular, low shrinkage.
Such properties are present in the liquid pulse-
sonority group-containing polyisocyanate mixtures of this
invention. Said mixtures have an isocyanate group content
of from 23 to 31 weight percent and are obtained through the
partial trimerization of a mixture of from about 80 to about
30 weight percent 4,4'-diphenylmethane diisocyanate, based
on the total weight, and from about 20 to about 70 weight
percent 2,4'-diphenylmethane diisocyanate, based on the
total weight, in the presence of a trimerization catalyst
with the subsequent deactivation of the trimerization
catalyst.
-- 4 --
~L227Z~33
The polyi~ocyanate mixture of the invention are
not only highly storage stable but they are easy to process
in the preferred range of isocyanate content due to their
viscosity. Cellular and noncellular polyurethane or polyp
urethane group-containing polyisocyanurate plastics prepared
from the polyisocyanates are surprisingly colorless and
exhibit almost no shrinkage. In this way nearly white rigid
foams with good mechanical and flame retardant properties as
well a a low smoke density can be obtained based on
diphenylmethane diisocyanates. Light colored rigid foams
are particularly desired for refrigerator insulation and in
sporting goods applications, for example, in surfboards.
Noncellular polyurethane prepared from the
polyisocyanates of the invention exhibit a significantly
lower reduction in impact strength after conditioning at
high temperatures, for example, at 200C, as is common in
the oven baked painting of thermobreak window moldings with
powder paints. In particular, such plastics exhibit high
dimensional stability at elevated temperatures.
Another advantage of the present invention is that
it is easier to control the reaction used to prepare
isocyanurate group-containing polyurethane foams. Unlike
isocyanurate group-containing polyurethane foams from
mixtures of diphenylmethane diisocyanates and polyphenyl-
polyethylene polyisocyanates, subsequently referred to as
~27~ I
crude MID, the polyi~ocyanates of the invention harden all
the way through in comparable tire period.
The functionality of the polyisocyanate mixture
can be adjusted across a wide range by altering the degree
of trimerization and the isocyanurate group content. This
leads to a wider range of possibilities for adjusting the
foams to meet desired mechanical properties such as abrasion
resistance, shrinkage, dimensional stability at elevated
temperatures, flammability, etc., in the vinyl product.
Description of the Preferred Embodiments
The following is noted relative to the initial
components and auxiliaries used for the polyisocyanate
mixtures of the invention:
The diphenylmethane diisocyanate mixtures which
are partially trimerized contain from about 80 to about 30
weight percent, preferably from 60 to 40 weight percent, and
more preferably from 55 to 45 weight percent, 4,4'-diphenyl-
methane diisocyanate and from about 20 to about 70 weight
percent, preferably from 40 to 60 weight percent, and more
preferably from 45 to 55 weight percent, 2,4'-diphenyl-
methane diisocyanate, whereby the weight percents are based
on the total weight of 4,4'- and 2,4'-diphenylmethane
diisocyanate.
However, mixtures which also contain Dow-
phenylmethane diisocyanate in amounts of maximum 5 weight
Lyle
percent, preferably less than 2 weight percent, based on the
weight of 4,4'- and 2,4'-diphenylmethane disunites are
also suitable. Such diphenylmethane diisocyanate mixtures
can be prepared through the phosgenation of diphenylmethane
dominoes or through complete or partial distillation ox the
diphenylmethane diisocyanate fraction off the crude MID.
The following typically may be used as trimmers-
lion catalysts: alkali or alkaline earth hydroxides, strong
organic bases such as, for example, Mannish bases and 1,3,5-
tris(N,N-dialkylaminoalkyl)-s-hexahydrotriazines, tertiary
amine, for example, triethylamine, basic salts of organic
carboxylic acids, for example, potassium acetate, Friedel
Craft catalysts, alkali metal oxides, alkali metal alcohol-
ales, fanlights, and carbonates, opium compounds of
nitrogen, phosphorus, and sulfur, and mono-substituted
monocarbamates. The following are preferably used: 1,3,5-
tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine,, co-
catalyst systems of 1,3,5-tris(N,N-dimethylaminopropyl)-s-
hexahydrotriazines, and organic moo- and/or dicarboxylic
acids, 2,4,6-tris(dimethylaminomethyl)phenols, ortho- Andre
para-dimethylaminomethylphenol, and adduces of one mole
1,3,5-tris(dialkylaminoalkyl)-s-hexahydrotriazine,, one mole
alkaline oxide, preferably ethylene or l,2-propylene oxide,
and one mole of an aliphatic or aromatic carboxylic acid.
An adduce of 1,3,5-tris(dimethylaminopropyl)-s-hexahydrotri-
~Z~7~2~3
amine, 1,2-propylene oxide and 2-ethylhexanoic acid ha
proven to be an especially good trimerization catalyst and
it, therefore, preferably used for this purpose. One
advantage in using this adduce it that the catalyst does not
need to be deactivated after trimerization is completed,
provided that the conversion takes place at temperature
between 25 and Luke. Here the required amount of catalyst
depends on the desired isocyanate content in the pulse-
Nate mixture and on the content of easily hydrolyzable
chlorine in the diphenylmethane diisocyanate mixture. The
trimerization catalysts are best used in amounts from 0.005
to 1.0 parts by weight, preferably from 0.01 to 0.1 parts by
weight, per 100 parts by weight of the mixture of 4,4'- and
2,4'-diphenylmethane-diisocyanate.
After the desired isocyanate content ha been
attained, the trimerization it stopped. If the trimmers-
lion catalyst doe not slowly decompose under the applied
reaction condition so that its final concentration is
- nearly zero, or if it does not lose it activity at room
temperature, it must be deactivated by the addition of a
suitable additive. Strong acids or carboxylic halogenide~
are among the suitable deactivation agents. Typical
deactivators are acids, for example, phosphoric acid,
hydrochloric acid, sulfuric acid, acetic acid, oxalic acid,
methanesulfonic acid, trifluoromethanesulfonic acid and
2~3
toluenesulfonic acid, and acid halogenide~ such as acutely
chloride, bouncily chloride, and toluenesulfonyl chloride.
In general, the trimerization reaction is effectively ended
by the addition of approximately 1 to 20, preferably 1 to 3,
equivalents of strong acid, carboxylic acid halogen ides
and/or toluenesulfonyl chloride per equivalent catalyst
and/or by cooling or quenching the reaction mixture.
The polyisocyanate mixtures of the invention can
be directly processed into nearly colorless polyurethane or
polyurethane group-containing polyisocyanurate plastics.
However, when the inherent color in the final product is
less important and other properties needed for the applique-
lion must be modified effectively, it is desirable to mix
the polyisocyanurate group-containing polyisocyanate
mixtures with other aliphatic, cycloaliphatic, or aromatic
polyisocyanates. Polyisocyanate mixtures of the type cited
are comprised of approximately 100 to 60 weight percent,
preferably about 95 to about 60 weight percent, of the
polyisocyanate mixture of the invention containing issues-
curate groups and approximately 0 to 40 weight percent,
preferably 5 to 40 weight percent, of an aliphatic, cycle-
aliphatic, and preferably aromatic polyisocyanate.
Typical isocyanates which may be used in admixture
with the modified isocyanates of this invention are:
aliphatic diisocyanates such as 1,4-butane-, try-
~22~
methyl-1,6-hexane- and, preferably, 1,6-hexane-diisocyanate,
cycloaliphatic polyi~ocyanate~ such a 3-isocyanatomethyl-
3,5,5-trimethylcyclohexyl isocyanate, 1-methyl-2,4- and/or
2,6-cyclohexane diisocyanate, 4,4'-, 2,4'-, duskily-
hexylmethane diisocyanate, mixtures of 4,4'- and 2,4'-
dicyclohexylmethane diisocyanate, or mixtures of 4,4'-,
2,4'- and 2,2'-dicyclohexylmethane diisocyanate, and
polycyclohexyl polyethylene polyisocyanates, and preferably
aromatic, in some cases carbodiimide and/or preferably
urethane group-containing polyisocyanates such as 2,4-
and/or Tulane diisocyanate, crude MID, naphthylene
disunites, urethane modified 4,4'-diphenylmethane
diisocyanates, urethane modified mixtures of 4,4'- and 2,4'-
diphenylmethane diisocyanaes, and urethane modified
mixtures of crude MID. The polyisocyanates can be singly or
in the form of mixtures.
To prepare the isocyanurate group-containing
polyisocyanates, the mixtures of 4,4'- and 2,4'-diphenyl-
methane diisocyanates, which can be utilized in accordance
with the invention, are mixed at temperatures from 0C to
160C, preferably from 0C Jo 30C, with the trimerization
catalyst, whereby the quality of the final product is
improved by adding the trimerization catalyst at the lowest
possible temperatures up to room temperature. Finally, the
reaction is allowed to take place at these temperatures,
-- 10 --
~22~7~3
however, preferably at from 25C to 100C and more prefer-
ably at from 30C to 80C, whereby mixing it desirable,
until an isocyanate content of from 23 to 31 weight percent,
preferably from 25 to 28 weight percent, based on the weight
of the polyisocyanate mixture is attained. To do this,
generally reaction times of from 0.3 hour to 60 hour,
preferably from 0.75 hour to 4 hours, are required. After
the desired isocyanate content has been attained, the
reaction mixture is allowed to cool and the trimerization
catalyst is deactivated to the extent necessary. The
deactivating agent can be incorporated in the reaction
mixture but can also be incorporated at the trimerization
temperature.
When using diphenylmethane diisocyanate mixtures
with high 4,4'-diphenylmethane diisocyanate contents, the
resulting polyisocyanate mixtures can exhibit a slight
turbidity which may be filtered off if needed.
The isocyanurate group-containing polyisocyanate
mixtures of the invention possess, as already stated, an
isocyanate content of from 23 to 31 weight percent, prefer-
ably from 25 to 28 weight percent, an isocyanurate group
content of from 10.0 to 2.6 weight percent, preferably from
8.6 to 5.6 weight percent, and a viscosity of from 20 to
200,000 ma preferably from 300 to 12,000 maps, at 25C.
7;2~
The compounds are valuable raw materials for the
preparation of cellular or dense polyurethane or polyp
urethane group-containing pQlyisocyanurate plucks, in
particular for the preparation of essentially colorless
rigid foams.
The polyi~ocyanate mixtures of the invention can
also be trimerized in the presence of organic solvent.
Solvents which do no react with isocyanates can be
utilized, for example, ethylene chloride, chloroform,
chlorobenzene, acetone, methylethylketone, ethyl acetate,
bottle acetate, tetrahydrofuran, Dixon, dimethylformamide,
Tulane, and zillion.
After completion of trimerization, the non-
converted 4,4'- and 2,4'-diphenylmethane diisocyanates and,
if desired, the solvent, can be separated off under non-
destructive conditions. This can be achieved by high vacuum
distillation in suitable evaporators or through extraction
with solvents in which only the diphenylmethane diisocyanate
but not the isocyanurate group-containing polyisocyanates
are soluble, for example, in aliphatic or cycloaliphatic
hydrocarbons.
The solvent-containing polyisocyanate mixtures of
the invention are typically used for polyurethane paints or
adhesives.
- 12 -
Z7;2~3
The preparation of the polyurethane or polyp
urethane grsup-containing polyisocyanurate plastics is
achieved by reacting the iqocyanurate group-containing
polyisocyanates of the invention with polyols and, in some
caves, chain extenders in the presence of catalyst and, in
some cases, blowing agents, auxiliaries, and additives.
Typical pOlyOlA utilized for this purpose are:
polyester polyols bayed on organic dicarboxylic acid,
preferably aliphatic dicarboxylic acids having from 2 to 12,
preferably 4 to 8, carbon atoms in the alkyd residue, and
polyfunctional alcohols, preferably dills, having function-
amities from 2 to 6, preferably 2 to 4, and hydroxyl numbers
from 20 to 700, whereby preferably polyester polyols hazing
hydroxyl numbers from 20 to 85 are used for the preparation
of flexible plastics, preferably polyester polyol~ having
hydroxyl numbers from 85 to lS0 are used for the preparation
of semi-rigid plastics, and preferably polyester polyols
having hydroxyl numbers from 200 to 490 are used for the
preparation of rigid cellular plastics. Typical examples
are aliphatic dicarboxylic acids such as succinic acid,
glutaric acid, pimelic acid, undecanedioic acid, dodecane-
Dick acid, and, preferably, adipic acid and aromatic
dicarboxylic acids such a phthalic acid and terephthalic
acid. Examples of dip and polyfunctional alcohols, in
particular difunctional alcohols, are: 1,2~ or 1,3-propane-
- 13 -
~27;~3
dill, dipropylene glycol, 1,5-pentamethylene glycol, 1,8-
octamethylene glycol, l,lO-decamethylene glycol, glycerine,
trimethylolpropane, pentaerythritol as well a sugar
alcohols, for example, sorbitol and, preferably, ethylene
glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexa-
ethylene glycol. In addition, alkanolamine~, dialkanol-
amine, and trialkanolamines, for example, ethanol amine,
diethanolamine, triethanolamine, and triisopropanolamine can
be used as polyfunctional alcohols. The cited dicarboxylic
lo acids and polyfunctional alcohols can be utilized in the
form of mixtures. Especially successful, and thus prefer-
ably used, are: polyester polyols of adipic acid or
mixtures of succinic, glutaric, and adipic acid and dip
ethylene glycol, and alcohol mixtures of ethylene
glycol/1,4-butanediol, ethylene glycol/diethylene glycol,
ethylene glycol/trimethylolpropane, diethylene glycol/tri-
methylolpropane, ethylene glycol/pentaerythritol, ethylene
glycol/triisopropanolamine, and diethylene glycol/triiqo-
propanolamine.
In place of the cited polyester polyols, which can
be utilized either individually or as mixtures, homogenou~
mixtures of polyester polyol~ and soluble organic combo-
newts, which are liquid at temperatures from lo to 30~C, can
be utilized, for example, hydroxyl group-containing polyp
esters of aromatic dicarboxylic acids and, preferably,
unsubstituted, linear Doyle.
- 14 -
2~3
However, polyether polyols having functionalitie~
from 2 to 8, preferably 2 to 4, and hydroxyl numbers from 25
to 800, preferably from 25 to 85, are preferably used for
flexible, dense or cellular plastic while such polyols
having hydroxyl number from 85 to 180 are utilized for
semi-rigid plastics and those having hydroxyl numbers from
200 to 600 are utilized for rigid, dense or cellular
plastic, are prepared according to known procedures, for
example, through anionic polymerization with alkali
hydroxides such as sodium or potassium hydroxide, or alkali
alcoholates such a sodium or potassium methyl ate, ethyl ate,
or potassium isopropyl ate as catalysts, or through cat ionic
polymerization with Lewis acids such as antimony pent-
chloride, boron fluoride ether ate, etc., as catalysts from
one or more cyclic ethers having from 2 to 4 carbon atoms in
the alkaline residue and an initiator molecule having from 2
to 8 active hydrogen atoms, preferably from 2 to 4.
Suitable cyclic ethers are, for example: twitter-
hydrofuran, 1,3-propylene oxide, 1,2- or battalion oxide,
styrenes oxide, epichlorohydrin, and, preferably, ethylene
oxide and l/2-propylene oxide. The alkaline oxides can be
utilized individually, alternating one after another, or as
mixtures. Typical initiator molecules are: water, organic
dicarboxylic acids such as succinic acid, adipic acid,
phthalic acid, and terephthalic acid, aliphatic and art-
- 15 -
%7~3
matte, in some kiwi, N-mono-, NUN-, and N,N'-dialkyl-
substituted Damon having from 1 to 4 carbon atom in the
alkyd residue such as, in some case, moo- and dialkyl-
substituted ethylenediamine, diethylenetriamine, in-
ethylenetetramine, l,3-propanediamine, 1,3- or 1,4-butane-
Damon, 1,2-, 1,3-, 1,4-, 1,5-, or 1,6-hexanediamine,
phenylenediamines, 2,4- or 2,6-toluenediamine, and 4,4'-,
2,4'-, or 2,2'-diaminodiphenylmethane. Particularly
interesting polyether polyols prepared from the compounds of
the group cited are: N,N,N',N'-tetrakis(2-hydroxyethyl)-
e~hylenediamine, N,N,N',N'-tetra~iq(2-hydroxypropyl)-
ethylenediamine, N, N, N ', N", N 1 -pentakis~2-hydroxypropyl)-
diethylenetriamine, phenyldiisopropanolamine, and higher
molecular weight alkaline oxide adduces of aniline.
Further starter molecule are alkanolamines such
as ethanol amine, diethanolamine, N-methyl- and N-ethyl-
ethanol amine, N-methyl- and N-ethyldiethanolamine, and in-
ethanol amine, ammonia, hydrazine, and hydrazides. Prefer-
ably used are polyfunctional, in particular dip and/or in-
functional, alcohols such as ethylene glycol, 1,2- and 1,3-
propanediol, diethylene glycol, dipropylene glycol, 1,4-
butanediol, 1,6-hexamethylene glycol, glycerine, in-
methylolpropane, pentaerythritol, sorbitol, and sucrose.
The polyether polyols can be utilized individually
or in the form of mixtures just as the polyester polyols.
- 16 -
I
Crystallite suspensions, as described in German
Patent Application P 30 01 462.1, can Allah be utilized as
polyols. They can either be utilized individually or in the
form of mixtures.
Among the blowing agents which can be used to
prepare cellular plastic is water, which react with
isocyanate groups to form carbon dioxide. The amounts of
water which can be used to advantage are from 0.1 to 3
weight percent based on the weight of polyisocyanate,
respectively from 0.1 to 2 weight percent based on the total
weight of the polyisocyanate and polyol. In some cases,
larger amounts of water can also be used.
Other blowing agents which can be used are low-
boiling-point liquids which evaporate due to the exothermic
polyaddition reaction. Here liquids which are inert with
respect to the organic polyisocyanate and have boiling
points of less than 50C are suitable. Examples of such
preferably utilized liquids are halogenated hydrocarbon
such as ethylene chloride, trichlorofluoromethane, dip
chlorodifluoromethane, dichloromonofluoromethane, dichloro-
tetrafluoroethane, and l,1,2-trichloro-1,2,2-trifluoro-
ethanes Mixtures of these low-boiling-point liquid
together and/or with other substituted or unsubstituted
hydrocarbons can also be used.
- 17 -
~t72~3
The most suitable amount of low-boiling-point
liquid used for the preparation of the cellular plastics
depend on the desired foam density and, in some caves, on
the additional utilization of water. In general, amounts
ranting from 5 to 40 weight percent based on 100 parts by
weight organic polyisocyanate, respectively from 2 to 30
percent based on the total weight of the polyisocyanate and
polyol offer satisfactory results.
Suitable kettle is to function between the
polyols, in Rome cases water, and the polyisocyanates are,
for example, tertiary amine such as dimethylbenzylamine, 2-
(dimethylaminoethoxy)ethanol, NUN ,N'-tetramethyldiamino-
ethyl ether, bis(dimethylaminopropyl)urea, N-methyl-
respectively N-ethylmorpholine, dimethylpiperazine, 1,2-
dimethylimidazole, l-aza-bicyclo(3,3,0)octane, and, prefer-
ably, triethylenediamine, metal salts such as tin dictate,
lead octet, tin diethylhexoate, and, preferably, tin (II)
salts and dibutyltin dilaurate as well as, in particular,
mixtures of tertiary amine and organic tin salts, from 0.1
to 5.0 weight percent catalyst bayed on the tertiary amine
and/or from 0.1 to 1.0 weight percent metal salts based on
the weight of the polyols are preferably used.
The standard cyclization and polymerization
catalysts for polyisocyanates have proved successful in
preparing polyurethane group containing polyisocyanate
- 18 -
plastic. Typical examples are: strong bases such a
qua ternary ammonium hydroxides, for example, benzyltrimsthyl
ammonium hydroxide, alkali metal hydroxides, for example,
sodium or potassium hydroxide alkali metal alkoxides, for
example, sodium methyl ate and potassium isopropyl ate;
trialkylphosphenes, for example, triethylphosphene, alkyd-
aminoalkylphenol~, for example, 2,4,6-tris(dimethylamino-
methyl phenol 3- and/or substituted pardons, for
example, 3- or 4-methylpyridine, metal organic salts, for
example, tetrakis(hydroxyethyl) sodium borate, Friedel-
Crafts catalyst, for example, aluminum chloride, iron (III)
chloride, boron fluoride, and zinc chloride, and alkali
metal salts of weakly organic acids and nitrophenolates, for
example, potassium octet, potassium 2-ethyl hexoate,
potassium bonniest, sodium pirate, and potassium phthal-
imide. Preferably, the strongly basic N,N'N"-tris(dialkyl-
aminoalkyl)-s-hexahydrotriazines are utilized, for example,
theN,N'N"-tris(dimethylaminopropyl)-s-hexahydrotriaziire, in
some cases in combination with aliphatic low molecular
weight moo- and/or dicarboxylic acids, for example acidic
acid and/or adipic acid, or aromatic carboxylic acids such
as benzoic acid.
The desired amount of isocyanurate group-forming
catalyst depends on the effectiveness of the catalyst being
used. In general, it has been found to be desirable to
-- 19 --
7Z~3
utilize from 1 to 15 parts by weight, preferably from 3.5 to
10 parts by weight catalyst, per 100 parts by weight organic
polyisocyanate.
In order to prepare urethane and polyisocyanurate
group-containing plastics, the catalysts assisting the
formation of urethane and isocyanurate groups can also be
mixed together.
The rigid foams are preferably prepared in the
presence of chain extenders or cross-linking agents. On the
other hand, it has been found to be advantageous to prepare
flexible cellular or dense polyurethane or polyurethane
group-containing polyisocyanurates with additional chain
extenders or cross-linking agents. Suitable chain extenders
or cross-linking agents possess molecular weights from 30 to
600, preferably from 60 to 300, and they preferably have two
active hydrogen atoms. Typical substances are: aliphatic
and/or aromatic dills having from 2 to 14 carbon atoms,
preferably from 2 to 6, such as propanediol, pentanediol,
1,6-hexanediol, and, preferably, ethanediol, 1,4-butanediol,
and bis(2-hydroxyethyl)hydroquinone, dominoes such as
ethylenediamine and, in some cases, 3,3'- respectively
Dow- respectively tetraalkyl-substituted 4,4'-
diaminodiphenylmethanes, ethanolamines such as triethanol-
amine, and polyhydroxyl compound such as glycerine,
trimethylolpropane, and low molecular weight hydroxyl group-
- 20 -
3~%~27;2~3
containing polyalkylene oxide from the previously mentioned
starting ~ub~tances.
Auxiliaries and additives can also be incorporated
in the reaction mixture. Typical are stabilizers, hydrolysis
inhibitors, pore regulator, fungi static and bacteriostatic
agents, colorant, pigments, fillers, surfactants, and
plasticizers.
Typical organic fillers are: rigid resins such as
those known a binders for the printing industry, for
example, those based on phenol, pine resin, or mailmen and
formaldehyde, polyester with melting points greater than
190C, preferably cross-linked polyesters based on dip
functional or higher functional carboxylic acids with divers
or with monomers, for example, (meth)acrylic acid derive-
lives, home- and copolymers of cyclopentadiene, kitten
resins, for example, those bayed on cyclohexanone, and rigid
polyurethane materials with melting points greater than
190C, for example, cross-linked polyurethane and issues-
curate group-containing polyurethane, polyvinyl chloride,
polyamide-6, and 6,6-acrylate graft rubbers, butadiene graft
rubbers, as well as polyvinyl acetate.
Inorganic fillers have proven to be particularly
suitable and are thus preferred: the conventional fillers,
reinforcing materials, weight increasing materials, agents
to improve the wear characteristics of paints, coatings,
etc. However, inorganic pigment can also be used. Typical
example are: silicate minerals, for example, lamellar,
silicates such as antigorite, serpentine, horn blends,
amphiboles, crystal, talcum, metal oxides such as kaolin,
aluminimum oxide hydrate, titanium oxides, iron oxides,
metal salts such as chalk, heavy spar, barium sulfate,
inorganic pigments such a cadmium sulfide, zinc sulfide,
and glass.
Typical auxiliaries are, for example, surfactant~
used to support the homogenization of the initial substances
and, in some cases, are also suitable for regulating the
cell structure. Typical examples are siloxane-oxyalkylene
heteropolymers and other organic polysiloxanes, oxyethylated
alkyd phenol, oxyethylated fatty alcohol, paraffin oils,
castor oil or acid esters of castor oil, and Turkish Red Oil
used in amount ranging from 0.1 part to 5 parts by weight
per loo parts by weight of the mixture of the polyisocyanate
and polyols.
Further information on the other additives cited
above can be found in the technical literature on the
subject, for example, in the monograph by J. H. Saunders and
K. F. Fresh, High Pollers Vol. XVI, Polyurethane Puts. 1
and 2, Verlag Intrusions Publishers, 1962 and 1964.
In order to prepare the flexible semi-rigid or
rigid cellular or dense polyurethane, the organic pulse
- 22 -
272~3
sonnets are reacted with the polyols, preferably polyester
and/or polyether polyols, and, in some kiwi, with chain
extenders or cross-linking agents in such amounts that the
ratio of reactive hydrogen atoms to isocyanate groups is
from 1:0.8 to 1:2.5, preferably from 1:0.9 to 1:1.2, and
more preferably approximately 1:1.
For polyisocyanates containing dense polyurethane
groups, the initial components are reacted in reactive
hydrogen atom-to-isocyanate group ratios of from 1:40 to
1:5, preferably from 1:30 to 1:15, and for corresponding
cellular polyisocyanurates from 1:40 to 1:2, preferably from
1:10 to 1:2.
The polyurethane or polyurethane group-containing
polyi~ocyanurate plastics are preferably prepared in a one-
; shot process. were the polyisocyanates are mixed with the
polyols, catalysts, and, in some cases, chain extenders or
cross-linking agents, blowing agents, auxiliaries, and
additives in a vigorous manner with the cited quantitative
ratios at temperatures from 0 to 50C, preferably from 15 to
40C, and then the reaction mixture is allowed to cure or
expand in open or closed molds.
The rigid foams produced from the polyisocyanate
mixtures of the invention are essentially white, exhibit
good flame inhibiting properties, produce a low smoke gas
density, and have good mechanical properties, in particular
compressive load strength.
- 23 -
~L22~ 3
The example which follow are designed to enable
those skilled in the art to practice the invention. The
parts referred to in the examples are by weight and the
temperature are in degrees centigrade unless otherwise
stated.
- 24 -
eye
Preparation of isocyanurate group-containing
polyisocyanate mixtures of 4,4'- and 2,4'-diphenylmethane
disunites.
Example 1
0.6 part try dimethylaminopropyl)-~-hexa-
hydrotriazine was dissolved in 5 parts dim ethyl phthalate
and were added to 3000 parts of a mixture comprising 47
weight percent 4,4'-diphenylmethane diisocyanate and 53
weight percent 2,4'-diphenylmethane diisocyanate in a 4-
liter glass flask. The resulting reaction mixture was
trimerized at this temperature for two hours while being
stirred, and then the formation of isocyanurate was teem-
inated by the addition of 1.5 parts bouncily chloride.
The resulting polyisocyanate mixture had an
isocyanate content of 26.9 weight percent and a vacuity of
1060 maps at 25C.
Example 2
0.72 part 1,3,5-tris(3-dimethylaminopropyl)-s-
hexahydrotriazine dissolved in 5 parts dimethylphthalate was
added to 3000 parts of the above-cited 4,4'- and 2,4'-
diphenylmethane diisocyanate mixture in a 4-liter glass
flask while mixing at 40C. The reaction mixture was then
trimerized for approximately 90 minutes at 80C. After an
isocyanate content of 25.7 weight percent was reached, the
- 25
72~
mixture was Wylie cooled to 23C, mixed at this temperature
for 18 hours, and the reaction was terminated by the
addition of 1.5 parts bouncily chloride. The resulting
polyi~ocyanate mixture had an isocyanate content of 24.1
weight percent and a viscosity of 10,700 mPaq at 25C.
Example 3
A series of three equal portions of 0.9 part of an
adduce prepared from one mole 1,3,5-tris(3-dimethylamino-
propyl)-s-hexahydrotriazine, one mole l,2-propylene oxide,
and one mole 2-ethyl hexanoic acid in the form of a 15
weight percent solution in dimethylphthalate was added to
3000 parts of a mixture of 4,4'- and 2,4'-diphenylmethane
diisocyanate in a weight ratio of 47:53 with an easily
hydrolyzable chlorine content of I ppm in a 4-liter glass
flask while mixing at 40C. After a reaction time of two
hours, the trimerization was stopped by adding 1 part
bouncily chloride.
The resulting polyisocyanate mixture had an
isocyanate content of 25.8 weight percent and a viscosity of
4500 maps measured at 25~C.
Example 4
14 parts of the above-cited trimerization catalyst
dissolved in 200 part dimethylphthalate was added in two
equal portions to 40,000 parts of a mixture comprising 4,4'-
and 2,4'-diphenylmethane in a weight ratio of 47:53 with an
- 26 -
~27~3
cagily hydrolyzable chlorine content of 70 ppm while
stirring at 40C. After a second addition of catalyst, the
temperature briefly rose to from 77 to 80C and then
returned to 40C. After an isocyanate content of 24.8
weight percent was reached, the reaction was terminated by
the addition of 13.5 parts bouncily chloride.
The resulting polyisocyanate mixture had a
viscosity of 9700 maps at 25C.
Examples 5-15
Here the same procedure was used as in Example 3,
except the 4,4'-/2,4'-diphenylmethane diisocyanate mixture
composition was varied, the amount of catalyst, and the
temperature of the added catalyst was also varied, so that
the isocyanurate group-containing polyisocyanate mixture
given in Table I were obtained.
- 27 -
7~3
g
O
V
Jo
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o o us o 8
v ox O o w o 0 o or a
mu o C4 In ox
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o Jo o o
Us
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Jo Z
v
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I=
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o o o o o o o o o o o
0 3 O o o o O o o o O o O
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--28--
Example 16
Eighty parts by weight of the isocyanurate group-
containing polyi~ocyanate mixture prepared in accordance
with Example 6 were mixed at room temperature with 20 parts
by weight of a mixture of 2,4- and Tulane doesn't
in a weight ratio of 80:20.
The resulting polyisocyanate mixture had an
isocyanate content of 29.5 weight percent and a viscosity at
25C of 550 ma
Example 17
The same procedure was followed as in Example 12,
however, the isocyanurate group-containing polyisocyanate
mixture and the Tulane diisocyanate mixture were combined
in a 90:10 weight ratio.
The no ulting polyisocyanate mixture had an
isn't content of 27.1 weight percent and a viscosity at
25C of 2100 ma
Preparation of rigid polyurethane group-containing pulse-
sonority foam.
General specifications for preparation:
A-Com~onent: Mixture of polyol, catalyst, foam stabilizer,
blowing agent, and, in some caves, flame retardant.
- 29 -
~L~2~3
B-Componen~: Mixture of diphenylme~hane diisocyanates and
polyphenyl-polymethylene polyisocyanate~ having an issues-
Nate content of 31 weight percent (crude MID).
Components A and B were vigorously mixed together
at 23C and allowed to expand freely in a box (dimensions
20x22x22 cm).
The type and quantity of initial components used,
the characteristic values and mechanical properties are
summarized in Table IT
The following abbreviations were used for the
initial components in Table II:
Crystallite
Suspension: Crystallite suspension having a hydroxyl
number of 265, comprised of 48 parts by
weight sucrose polyol, 28 parts by weight
diethylene glycol adipate, and 24 part
by weight neopentyl glycol isophthalate.
Swoop: Polyether polyol having a hydroxyl number
of 400, prepared from a mixture of
sucrose, triethanolamine, and water as
initiator molecules, and 1,2-propylene
oxide.
- 30 -
I
Pi: Polypropylene glycol having a hydroxyl
number of 240.
Ethanol: Thinly R 350 X, Jefferson polyether
polyol.
TCEP: Trichloroethyl phosphate.
DC 193: Foam stabilizer bayed on silicone, Dow
Corning product.
B 1903: Foam stabilizer based on silicone,
Gold Schmidt, En en product.
PI: Desmorapid~ PI polyurethane catalyst from
Bayer AGO
Cat. 1: Catalyst adduce based on pentamethyl-
diethylenetriamine, 1,2-propylene oxide
and 2-ethylhexanoic acid.
Cat 2: Potassium format, 35 weight percent
solution in ethylene glycol.
- 31
I 13
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Preparation of Rudy Polyurethane Foam
example 21
A-Com~nent: Mixture comprising 19.6 parts by weight of a
polyether polyol having a hydroxyl number of 400 prepared
from a mixture of sucrose, glycerine, and water as starter
molecules and 1,2-propylene oxide, 9.0 part by weight
N,N,N',N'-tetraki~(2-hydroxypropyl)ethylenediaminee, 25 parts
by weight phosphorus-containing flame retardant polyol
Idol B 251, Sylvia), 3 parts by weight glycerine, 16 parts
by weight tris(chloroethyl)phosphate, 1 part by weight
silicone stabilizer (Bayer A stabilizer OX 710), 0.7 part
by weight dimethylcyclohexylamine, 0.7 part by weight water,
and 32.5 parts by weight trichlorofluoromethane.
B-Component: 121.6 parts by weight of a partially issues-
unrated mixture of 2,4'- and 4,4'-diphenylmethane dozes-
notes in a 53:47 weight ratio with an isocyanate content of
25.6 weight percent prepared in accordance with Example 15.
The A and B components were vigorously mixed
together at 23C and were allowed to expand freely in a
carton having dimensions 20x22x22 cm.
The characteristic data measured for the resulting
polyurethane rigid foam and the mechanical characteristics
of same are summarized in Table III.
- 34 -
Z72~3
I
Example 22
A-Component: As in Example 21, but instead of 32~5 parts by
weight, only 30~8 parts by weight trichlorofluoromethane.
115.2 parts by weight of a partially issues-
unrated mixture of 2,4'- and 4,4'-diphenylmethanediisocya-
notes having an isocyanate content of 27.0 percent by weight
prepared in accordance with Example 14.
The A and B components were mixed together and
allowed to expand as in Example 21.
The characteristics and mechanical properties of
the resulting rigid polyurethane foam are summarized in
Table III.
A-Component: As in Example 21, but instead of 32.5 parts by
weight, 33.4 parts by weight trichlorofluoromethane were
used.
B-Component: 125 parts by weight of a partially issues-
unrated mixture of 2,4'- and 4,4'-diphenylmethane dozes-
notes hazing an isocyanate content of 24.9 weight percent
were prepared in accordance with Example 13.
The A and B components were mixed together and
allowed to expand as in Example 21.
The resulting rigid polyurethane foam coworkers-
tics and mechanical properties are summarized in Table III.
- 35 -
7~3
TABLE III
Examples 21 22 23
Characteristics:
Mixing time, sec. 20 15 20
Cream time, eke. 32 25 35
Gel time, eke. 96 80 95
Rise time, sec. - 135
Mechanical Properties:
Density, g/l 24.4 25.8 26.7
Compression Strength
per DIN 53 421, N/mm2 0.226 0.249 0.26
Compression at Failure
per DIN 53 421, 7.4 7.8 7.0
Flexural Strength
per DIN 53 423, (N/mm2) 0.243 0.282 0.30
Deflection at Break
per DIN 53 423, mm 13.1 11.5 11.5
Dimensional Stability
at Elevated Temperatures
per DIN 53 424, C 175 170 187
Preparation of Dense Polyurethane Group-Containin~ Polxiao-
senoritas
Examples aye and 24b
A-Component: Mixture comprising 98.2 parts by weight of a
graft polyether polyol dispersion having a hydroxyl number
of 29 and a copolymer content of 20 wright percent based on
the total weight prepared by in situ polymerization of a
mixture of styrenes and acrylonitrile at a 3:2 weight ratio
in the presence of a polyether polyol based on trimethylol-
propane, propylene oxide, and ethylene oxide, 0.5 part by
weight ortho-tetraethyl silicate, 1.20 parts by weight 40
percent solution of potassium acetate in ethylene glycol,
and 0.15 part by weight of an amidine tin Walt complex.
B-Component: Isocyanurate group containing polyisocyanate
mixture of 4,4'- and 2,4'-diphenylmethane diisocyanate in a
47:53 weight ratio having an isocyanate content of 26.2
lo weight percent prepared in accordance with Example 3.
One hundred parts by weight of the A component and
140 parts by weight (Example aye) or 160 parts by weight
(Example 24b) of the B component were processed with the aid
of a high pressure model Permute 30 Elastogran Maschinenbau
metering machine (Strasslach near Munich) and was processed
into molded boards in a closed metal mold having interior
dimensions of 4x400x400 mm using reaction injection molding
technique. The boards were able to be remolded after 20
seconds. The temperature of the A and B components in the
metal mold was 50C.
The mechanical properties of the molded board are
summarized in Table IV.
~L22~7Z~3
Comparison Example IV
_ opponent: As in Example aye.
B-Component: Mixture of 4,4'- and 2,4'-diphenylmethane
diisocyanate in a 47:53 weight ratio with an isocyanate
content of 33.6 weight percent.
With an OH:NCO group ratio corresponding to that
in Examples aye and 24b, in other words, a mixture ratio of
100 parts by weight A component to 110 parts by weight,
respectively 125 parts by weight of the B component, the
formulation could no longer be processed since the reaction
mixture golfed within from 1.5 to 3 seconds due to the
higher rate of isocyanuratization, 90 that the mold gore
could no longer be filled.
Comparison Examples Via and Vb
A-Component: Mixture comprising 98.67 parts by weight of a
graft polyether polyol dispersion as in Examples aye and
24b, 0.50 parts by weight ortho-tetraethyl silicate, 0.75
parts by weight 40 percent solution of potassium acetate in
ethylene glycol, and 0.08 parts by weight of an amidine zinc
salt complex.
B-Component: Mixture of 4,4'- and 2,4'- diphenylmethane
diisocyanate in a 47:53 weight ratio with an isocyanate
content of 33.6 weight percent.
One hundred parts by weight of the A component and
110 parts by weight (Comparison Example Vat respectively 125
- 38 -
122~72~
parts by weight (Comparison Example Vb) of the B component
were processed as in Examples aye and 24b into molded
boards. Because of the greatly reduced catalyst content,
remolding time was 60 second.
The mechanical properties measured on the molded
boards are summarized in Table IV.
- 39 -
7~3
r-
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E
x
En
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O o 0 o
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cry 0 1`
Jo I
Jo a
O I
m E
a x
Jo o Us o CO o Us
O Us
so
Jo O
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En
Jo
m I-
I:
En a
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Do
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Jo
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S JO
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aye
C Jo O
o
us I
o Jo a
I I a .
m
I, s E E Q --
Q I E S S to
S O I-- V a) o E:
Z Jo do 4 S O Jo
O I e .- s
v 3 f) C
ray Us If) O U) J- U') C
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r ox
X So C Z Z En Z E a O
I Eel I 1~1 I H a I H 2 H I
--40--
~2~%~3
Example aye and 24b show that the use of the
isocyanurate group-containing polyi~ocyanate mixture of the
invention produce molded board with a high impact
strength, which only are reduced by approximately 40 percent
at elevated temperatures (up to 120 minutes at 200C),
whereby this reduction does not increase progressively with
time. Particularly worth noting is the high dimensional
stability of the molded boards at elevated temperatures, in
particular the higher index.
In Comparison Examples Via and Vb, on the other
hand, a board was obtained whose impact strength reduced
sharply and progressively at elevated temperatures until the
material became unusable. A further disadvantage was the
low dimensional stability at elevated temperatures, making
the material unsuitable for thermal breaks in aluminum
window moldings which are subsequently powder coated.
41 -
